1. Field of the Invention
This invention concerns an improved synthetic pulp of oriented polyethylene fibrids, suited particularly for use in asbestos-reinforced articles as a replacement for the asbestos. The invention also concerns a process for preparing the pulp and articles reinforced with the pulp.
2. Description of the Prior Art
Pulps from synthetic organic polymers have been described by Morgan, U.S. Pat. No. 2,999,788. Synthetic polyolefin pulps are made commercially, as described, for example, by Kirk-Othmer: Encyclopedia of Chemical Technology, vol. 19, 3rd edition, p. 420-435 (1982). However, such pulps generally do not function well as reinforcing fibers.
Pulps of oriented polyethylene fibrids are disclosed in British Patent 891,945. Gale et al, U.S. Pat. No. 4,608,089, discloses incorporating such a pulp of oriented polyethylene fibrids into an aqueous slurry of Portland cement for making fiber-reinforced cement articles. The pulp is prepared from flash-spun plexifilaments which are cut into small pieces and beaten in an aqueous medium. In pulp-reinforced cement composites, the pulp constitutes from 0.1 to 10% of the weight of the dried and cured composite. Although these pulps have found some utility in such cement composites, improvements in these pulps could enhance their utility considerably in reinforced cements as well as expand their use into other end-uses.